A back electromotive force (BEMF) of a spindle motor in a hard disk drive is rectified and exploited to drive a voice coil motor (VCM) in the hard disk drive to retract the heads of the hard disk drive to a park position. The VCM is driven in a discontinuous mode comprising an alternation of VCM on-times and VCM off-times. Rectifying the BEMF of the spindle motor is discontinued before the end of the VCM off-times, Toff with the spindle motor brought into a brake condition wherein the spindle motor is short-circuited and the spindle BEMF forces currents through the windings of the spindle motor. The spindle current is thus pre-charged and made ready to cope with a VCM current request at the next VCM on-time.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The method of claim 1, wherein rectifying the BEMF of the spindle motor comprises one of synchronous rectification or synchronous spindle step-up.
3. The method of claim 1, further comprising discontinuing rectifying the BEMF of the spindle motor and bringing the spindle motor into the brake condition at an end of the VCM off-times.
4. The method of claim 1, further comprising discontinuing rectifying the BEMF of the spindle motor and bringing the spindle motor into the brake condition over a predetermined portion of the VCM off-times.
5. The method of claim 4, wherein the predetermined portion of the VCM off-times is a programmable portion of the VCM off-times.
6. The method of claim 1, further comprising controlling an intensity of spindle motor current with the spindle motor brought into the brake condition.
7. The method of claim 1, further comprising driving the at least one VCM in the hard disk drive to retract the heads of the hard disk drive to the park position with a constant velocity.
9. The control circuit of claim 8, further comprising the control circuit configured to rectify the BEMF of the spindle motor using one of synchronous rectification or synchronous spindle step-up.
10. The control circuit of claim 8, further comprising the control circuit configured to discontinue rectifying the BEMF of the spindle motor and bringing the spindle motor into the brake condition at an end of the VCM off-times.
11. The control circuit of claim 8, further comprising the control circuit configured to discontinue rectifying the BEMF of the spindle motor and bringing the spindle motor into the brake condition over a predetermined portion of the VCM off-times.
12. The control circuit of claim 11, wherein the predetermined portion of the VCM off-times is a programmable portion of the VCM off-times.
13. The control circuit of claim 8, further comprising the control circuit configured to control an intensity of spindle motor current with the spindle motor brought into the brake condition.
14. The control circuit of claim 8, further comprising the control circuit configured to drive the at least one VCM in the hard disk drive to retract the heads of the hard disk drive to the park position with a constant velocity.
16. The hard disk drive of claim 15, further comprising the control circuit configured to rectify the BEMF of the spindle motor using one of synchronous rectification or synchronous spindle step-up.
17. The hard disk drive of claim 15, further comprising the control circuit configured to discontinue rectifying the BEMF of the spindle motor and bringing the spindle motor into the brake condition at an end of the VCM off-times.
18. The hard disk drive of claim 15, further comprising the control circuit configured to discontinue rectifying the BEMF of the spindle motor and bringing the spindle motor into the brake condition over a predetermined portion of the VCM off-times.
19. The hard disk drive of claim 15, further comprising the control circuit configured to control an intensity of spindle motor current with the spindle motor brought into the brake condition.
20. The hard disk drive of claim 15, further comprising the control circuit configured to drive the at least one VCM in the hard disk drive to retract the heads of the hard disk drive to the park position with a constant velocity.
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August 9, 2023
October 15, 2024
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